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reg. #143 corrected translation of mpz_fdiv_q_2exp

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This commit is contained in:
czurnieden 2018-12-30 22:05:36 +01:00
parent 1eabbca8c4
commit af29c51921
1 changed files with 19 additions and 9 deletions
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28
bn_mp_prime_strong_lucas_selfridge.c
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@ -58,9 +58,15 @@ LBL_MPMULSI_ERR:
mp_clear(&t); mp_clear(&t);
return err; return err;
} }
#include <unistd.h>
/*
static void ltm_print(const char *s, mp_int *a){
printf("%s",s);
mp_fwrite(a,10,stdout); fflush(stdout);
puts("\n");
fflush(stdout);
}
*/
/* /*
Strong Lucas-Selfridge test. Strong Lucas-Selfridge test.
returns MP_YES if it is a strong L-S prime, MP_NO if it is composite returns MP_YES if it is a strong L-S prime, MP_NO if it is composite
@ -85,10 +91,9 @@ int mp_prime_strong_lucas_selfridge(const mp_int *a, int *result)
/* CZ TODO: Some of them need the full 32 bit, hence the (temporary) exclusion of MP_8BIT */ /* CZ TODO: Some of them need the full 32 bit, hence the (temporary) exclusion of MP_8BIT */
int32_t D, Ds, J, sign, P, Q, r, s, u, Nbits; int32_t D, Ds, J, sign, P, Q, r, s, u, Nbits;
int e; int e;
int isset; int isset, oddness;
*result = MP_NO; *result = MP_NO;
/* /*
Find the first element D in the sequence {5, -7, 9, -11, 13, ...} Find the first element D in the sequence {5, -7, 9, -11, 13, ...}
such that Jacobi(D,N) = -1 (Selfridge's algorithm). Theory such that Jacobi(D,N) = -1 (Selfridge's algorithm). Theory
@ -138,6 +143,8 @@ int mp_prime_strong_lucas_selfridge(const mp_int *a, int *result)
} }
} }
P = 1; /* Selfridge's choice */ P = 1; /* Selfridge's choice */
Q = (1 - Ds) / 4; /* Required so D = P*P - 4*Q */ Q = (1 - Ds) / 4; /* Required so D = P*P - 4*Q */
@ -232,6 +239,7 @@ int mp_prime_strong_lucas_selfridge(const mp_int *a, int *result)
} }
Nbits = mp_count_bits(&Dz); Nbits = mp_count_bits(&Dz);
for (u = 1; u < Nbits; u++) { /* zero bit off, already accounted for */ for (u = 1; u < Nbits; u++) { /* zero bit off, already accounted for */
/* Formulas for doubling of indices (carried out mod N). Note that /* Formulas for doubling of indices (carried out mod N). Note that
* the indices denoted as "2m" are actually powers of 2, specifically * the indices denoted as "2m" are actually powers of 2, specifically
@ -272,7 +280,8 @@ int mp_prime_strong_lucas_selfridge(const mp_int *a, int *result)
e = isset; e = isset;
goto LBL_LS_ERR; goto LBL_LS_ERR;
} }
if (isset == MP_YES) {
if (isset == MP_YES) { puts("HERE");
/* Formulas for addition of indices (carried out mod N); /* Formulas for addition of indices (carried out mod N);
* *
* U_(m+n) = (U_m*V_n + U_n*V_m)/2 * U_(m+n) = (U_m*V_n + U_n*V_m)/2
@ -280,7 +289,6 @@ int mp_prime_strong_lucas_selfridge(const mp_int *a, int *result)
* *
* Be careful with division by 2 (mod N)! * Be careful with division by 2 (mod N)!
*/ */
if ((e = mp_mul(&U2mz, &Vz, &T1z)) != MP_OKAY) { if ((e = mp_mul(&U2mz, &Vz, &T1z)) != MP_OKAY) {
goto LBL_LS_ERR; goto LBL_LS_ERR;
} }
@ -309,10 +317,11 @@ int mp_prime_strong_lucas_selfridge(const mp_int *a, int *result)
* Thomas R. Nicely used GMP's mpz_fdiv_q_2exp(). * Thomas R. Nicely used GMP's mpz_fdiv_q_2exp().
* But mp_div_2() does not do so, it is truncating instead. * But mp_div_2() does not do so, it is truncating instead.
*/ */
oddness = mp_isodd(&Uz);
if ((e = mp_div_2(&Uz, &Uz)) != MP_OKAY) { if ((e = mp_div_2(&Uz, &Uz)) != MP_OKAY) {
goto LBL_LS_ERR; goto LBL_LS_ERR;
} }
if ((Uz.sign == MP_NEG) && (mp_isodd(&Uz) != MP_NO)) { if ((Uz.sign == MP_NEG) && (oddness != MP_NO)) {
if ((e = mp_sub_d(&Uz, 1uL, &Uz)) != MP_OKAY) { if ((e = mp_sub_d(&Uz, 1uL, &Uz)) != MP_OKAY) {
goto LBL_LS_ERR; goto LBL_LS_ERR;
} }
@ -325,10 +334,11 @@ int mp_prime_strong_lucas_selfridge(const mp_int *a, int *result)
goto LBL_LS_ERR; goto LBL_LS_ERR;
} }
} }
oddness = mp_isodd(&Vz);
if ((e = mp_div_2(&Vz, &Vz)) != MP_OKAY) { if ((e = mp_div_2(&Vz, &Vz)) != MP_OKAY) {
goto LBL_LS_ERR; goto LBL_LS_ERR;
} }
if ((Vz.sign == MP_NEG) && (mp_isodd(&Vz) != MP_NO)) { if ((Vz.sign == MP_NEG) && (oddness != MP_NO)) {
if ((e = mp_sub_d(&Vz, 1uL, &Vz)) != MP_OKAY) { if ((e = mp_sub_d(&Vz, 1uL, &Vz)) != MP_OKAY) {
goto LBL_LS_ERR; goto LBL_LS_ERR;
} }